15... h8h5 This is a \"mysterious rook move,\" although I suspect not the type that inspired Nimzowitsch to write about this theme in his classical book \"My System.\" Harikrishna blocks the advance of the h-pawn, but White can still open the game on the queenside when Black may be left with a misplaced rook. 16. f1e2 The position of the rook is shaky on h5. 16... d7b6  17. e3e4  17... b6c4 It's clear that Black is in big trouble here. White has many tempting continuations.